Structures that provide siege health could also provide city stability?

[clear arrow]

Wooden palisades +5 stability
Stone walls +5 stability
Archer battlements +5 stability etc.

game roleplaying explanation for +city stability of defensive structures:

A stone wall: the citizens inside the city would feel more safe & secure... 🙂
Ballista towers: if there's an angry mob of rebellious citizens, simply turning the ballista towers inwards solves the potential riot. Their simple presence in the city would give +5 stability. 😄

[boreal moat]

I feel like this would be interesting as part of a society trait to favor defensive structures rather than a baseline bonus.